In general, fundamental steps of processing color light-sensitive materials are a color developing step and a desilvering step (i.e., a step removing silver). That is, exposed silver halide color photographic materials are introduced to the color-developing step. In this step, silver halide is reduced with a color developing agent to produce silver, and the oxidized color developing agent in turn reacts with a color former to provide a dye image. Then, the color photographic material is subjected to the desilvering. In this step, silver having been produced in the preceding step is oxidized by the action of an oxidant (commonly called bleaching agent, and then dissolved with a silver ion-complexing agent (commonly called fixing agent) to remove. Therefore, only dye images remain in the photographic materials having been subjected to these processing. In addition to the two fundamental steps of color development and silver removal (desilvering), practical development processing involves auxiliary steps for, for example, maintaining photographic and physical quality of images and improving shelf life of image. There are illustrated, for example, a hardening bath for preventing light-sensitive layers from being softened too much during processing, a stopping bath for effectively stopping development reaction, an image-stabilizing bath for stabilizing image, and a film-removing bath for removing a packing layer of a support.
The above-described desilvering step may be conducted in two manners: in one step, silver removal (desilvering) is conducted in two steps using separately a bleaching bath and a fixing bath; in another manner, silver removal is conducted in one step using a bleach-fixing bath wherein a bleaching agent and a fixing agent are allowed to coexist for accelerating the processing and saving work, thus the processing being conducted more simply.
In recent processing of color photographic light-sensitive materials, a bleaching process using mainly a ferric ion complex salt (for example, iron(III) aminopolycarboxylate complex salts, particularly iron(III) ethylenediaminetetraacetate complex salt) is predominantly employed in view of acceleration and simplification of the processing and prevention of environmental pollution.
However, ferric ion complex salts have a comparatively small oxidizing ability and, therefore, show an insufficient bleaching power. Hence, a bleaching or bleach-fixing processing using the ferric ion complex salt has the defect that, though the salt provide satisfactory results with, for example, low-speed silver halide color photographic material containing mainly a silver chlorobromide emulsion, it shows only insufficient bleaching action to cause insufficient removal of silver or require a long time for bleaching with respect to high-speed silver halide color photographic materials containing mainly a silver chlorobromoiodide emulsion or a silver bromoiodide emulsion and having been color-sensitized, particularly color light-sensitive materials and color negative light-sensitive materials for photographing use.
As bleaching agents other than the ferric ion salts, there are known persulfates which are usually used together with chlorides as a bleaching solution. However, a bleaching solution using the persulfate has the defect that the persulfate has weaker bleaching power than the ferric ion complex salts and therefore requires a extremely long time for bleaching.
In general, bleaching agents causing no environmental pollution or having no corrosive properties to apparatuses have a weak bleaching power. Thus, it has been desired to increase bleaching ability of a bleaching or bleach-fixing solution using a bleaching agent with a weak bleaching power, particularly a ferric ion complex salt or a persulfate salt.
For this purpose, Research Disclosure No. 24023 (April, 1984), JP-A-230653 (The term "JP-A" as used herein means an "unexamined published Japanese Patent application"), etc. describe processings of using two or more of various iron(III) aminopolycarboxylate complex salts. These processings, however, fail to provide satisfactory results.
On the other hand, Research Disclosure, No. 24241 and ibid., No. 11449, and JP-A-61-201247 give descriptions regarding bleaching accelerator-releasing couplers.
It is described therein that the use of these couplers serve to shorten bleaching time. However, the use of these couplers is still insufficient and, when bleaching time is greatly shortened, there results insufficient silver removal (i.e., insufficient desilvering). In addition, it has become apparent that, they have a serious defect that the effect of these couplers is descreased in running state in continuous processing using an automatic developing machine, which is an ordinary processing manner.